Many studies have reported a significant association between childhood maltreatment and substance use in young adulthood. However, the specific mechanisms connecting childhood maltreatment with substance use in young adulthood remains poorly understood. The overall goal of this study is to examine whether the association is mediated by individual self-regulation processes. Since young people have much greater freedom from social control and parental monitoring during young adulthood than they ever did in the past, clarity about the role of self-regulation is central to our understanding of escalated substance use in young adulthood among victims of childhood maltreatment. If self-regulation can be identified as a mechanism through which exposure to childhood maltreatment influences substance use later in young adulthood, and key aspects of self-regulation processes can be specified, new intervention approaches can be developed. Unique novel features of this study include an emphasis on emotional self-regulation which has been overlooked in addiction research, a comprehensive four-dimensional conception of self-regulation (i.e., good emotional self-regulation, poor emotional self-regulation, good behavioral self-regulation, and poor behavioral self-regulation) in contrast to other research that focuses on only one or two dimensions, and comprehensive measures of childhood maltreatment including timing, duration, severity, and types of maltreatment. Using a community sample of 160 medically healthy young adults (ages 18-25), half with exposure to childhood maltreatment (N=80), and half without exposure to childhood maltreatment (N=80), this study has the following aims: (1) To examine if the presence of childhood maltreatment is associated with poor emotional and/or behavioral self-regulation processes;2) To investigate if poor emotional and/or behavioral self-regulation processes are associated with substance use in young adulthood;and 3) To examine if the association between childhood maltreatment and substance use in young adulthood are mediated by emotional and/or behavioral self-regulation processes. For more rigorous evaluation of the role of four types of self-regulation processes in understanding childhood maltreatment and substance use comorbidity in young adulthood, we also test alternative mechanisms including posttraumatic stress disorder (PTSD) and antisocial behavior. The findings of the current study help to explain which of four types of self-regulation are more predictive of substance use in young adulthood. PUBLIC HEALTH RELEVANCE: This research is designed to elucidate the relationship between exposure to childhood maltreatment and substance use in young adulthood. The primary factor postulated to link this relationship is individual self- regulation capacities. The results of this research will help determine intervention targets to prevent substance use in young adulthood by enhancing maltreated individuals'self-regulation processes.